More than a year after the FBI began their investigation into the horrible slaughter of 58 people — and the wounding many others — at a Las Vegas country concert, the FBI said Tuesday it hadn’t concluded anything more about Stephen Paddock‘s motive for the attack than it had the day after the shooting stopped.

The FBI’s conclusions on the mass murder, which Stephen Paddock undertook from a window in the Mandalay Resort and Casino in October 2017, were unveiled on Tuesday by the Associated Press. The attack at the Route 91 Harvest Festival was the deadliest mass shooting in modern U.S. history.

The FBI concluded what we already know, that Paddock acted alone when he planned and carried out the attack, Aaron Rouse, the special agent in charge of the FBI’s Las Vegas office, said. The 64-year-old fatally shot himself as police arrived into his hotel suite.

But after 16 months of study and analysis by agents and behavior specialists, the FBI have not found out why Paddock did it.